Sheet positioning mechanism



Feb; 28, 1967 c. N. BEER SHEET POSITIONING MECHANISM 2 Sheets-Sheet 1 Fil ed March so, 1964 l'n've-mor' CLIFFORD NOR THMORE BEER Atto n Feb. 28, 1967 c. N. BEER 3,306,608

SHEET POSITIONING MECHANISM I Filed March 30, 1964 2 Sheet S-Sheet 2 Inventor CLIFFORD NORTHMORE BEER Attorne 3,306,608 SHEET POSITIONING MECHANISM Clifford N. Beer, 15 Queen Eleanors Road, Onslow Village, Guildford, Surrey, England Filed Mar. 30, 1964, Ser. No. 355,696 Claims priority, application Great Britain, Jan. 6, 1964, 550/64 3 Claims. (Cl. 271-53) This invention relates to a sheet positioning mechanism, especially a sheet positioning mechanism for use in a machine for slitting relatively stiff sheets, for example mild steel or like metal sheets, into separate smaller sheets.

The object of this invention is to ensure that sheets are automatically correctly aligned so that they will be accurately slit along one or more predetermined lines, and to this end according to this invention there is provided a sheet positioning mechanism comprising feeding means adapted initially to engage a sheet to be slit and feed it towards a slitting member, said feeding means being so formed as to allow the sheet an angular or skewing movement in relation thereto, aligning means against which the leading edge of the sheet is fed before it reaches said slitting member, the angular or skewing movement allowed by the feeding means serving to ensure that the sheet becomes correctly aligned, that is, as dictated by the aligning means, before slitting of the sheet commences.

According to a preferred feature of this invention, the feeding means comprises a pair of roller elements, one or both of which is or are crowned or otherwise formed to provide a point contact with a sheet being fed, such contact allowing the sheet the required angular or skewing movement.

According to another preferred feature of this inven tion, the aligning means comprises one or more retractable elements which will be engaged by the leading edge of the sheet prior to the slitting thereof and then automatically withdrawn as slitting commences. Thus, a pair of laterally spaced pawls may be provided, each pawl being carried by an arm or the like which is movable to effect retraction of the pawls, means being provided for automatically returning the arms to their initial position before a further sheet to be slit is fed by the said roller elements.

In the accompanying drawings:

FIGURE 1 illustrates an installation for slitting sheets in which sheets are initially fed in one direction through a first slitting machine A, and the separate smaller sheets thus produced are fed in a direction at right angles to the said initial direction of feed to a second slitting machine B whereby they are slit into sheets of still smaller size, and

FIGURE 2 is a central transverse section through the machine B, being drawn on an enlarged scale.

In a slitting machine there are normally provided two elongated feed rollers which grip the edge of a sheet to be slit and feed it towards a slitting member. It will be understood that such rollers do not allow any angular or skewing movement of the sheet. Thus in the installation illustrated these feed rollers are omitted in the machine B and replaced by a pair of centrally disposed roller elements 12, the uppermost or both of which is or are crowned. The edge of a sheet to be slit will still be gripped between the rollers 1, 2 and the sheet will still be fed towards the slitting members 3, 'but the sheet will be capable of angular or skewing movements. The rollers United States Patent 3,306,608 Patented Feb. 28, 1967 1, 2, referred to hereinafter as the skew rollers may be supported by brackets 4, 5 conveniently mounted on the slitting machine frame 6.

Disposed on opposite sides of the centre line passing through the skew rollers 1, 2 perpendicular to the axes thereof are two arms 7 of approximately inverted L shape. Each arm is mounted at its lower end on a rockable shaft 8 to which it is splined, serrated, keyed or otherwise secured so that it can be longitudinally adjusted as dictated by the width of sheets being slit.

In the upper end portion of each arm 7, that is the shorter half of the L, there is rockably mounted a pawl block 9, this block being subject to a spring pressed plunger 10 so that normally the pawl 9 is projected upwardly from the arm 7.

When at rest, the two arms 7 are adapted to be held, by means which will be described in a moment, so that the two pawls 9 are in advance of the slitting members 3. Thus a sheet fed by the skew rollers 1, 2 contacts the pawls 9 before being engaged by the slitting members. If the sheet is fed crookedly it strikes one pawl first and then turns or skews until it strikes the other pawl. The sheet is thus automatically correctly aligned before slitting commences. As slitting commences the two arms 7 rock forwardly until the pawls 9 slip beneath the sheet.

The two arms 7 are rockable with their supporting shaft 8 against the force of spring means which serve always to return the arms, with the pawls, to their initial sheet alignmentposition. Thus-each arm has an extension 11 at its lower end adapted to abut against a spring pressed return plunger 12. Moreover, each arm has associated therewith a cam disc 13 formed with a shallow V-shaped notch 14 for co-operation with a second spring pressed plunger 15 for ensuring that the arm always returns to its correct sheet aligning position. As the arm rocks this second plunger rides up a curved cam face 16 which will compress the associated spring thereby providing assistance for the return of the arm.

To ensure that sheet contacts and remains in contact with the pawls, downwardly extending guide arms 17 or the like are provided, these arms being 'adjustably supported from the machine frame 6 and having appropriately chamfered underneath faces 19.

In like manner, of course, the pawl carrying arms 7 and the shaft and plungers associated therewith are conveniently mounted in brackets 20 provided on the machine frame 6.

It is understood that the present invention is not limited to the particular application described above.

Details of the slitting machines A and B generally have not been described. The construction thereof, including roller conveyors 30 is, it is believed, well known.

I claim:

1. A sheet positioning mechanism for use with a sheet I slitting device of the type described, comprising a pair of retractable stop members for the frontal sheet edge defining its position in front of the slitting device, each stop member consisting of a spring loaded retractable pawl; sheet feeding means point-contacting the sheet allowing the same a skewing movement to bring the front edge in simultaneous contact with both said pawls; a reciprocable support for each pawl causing the latter to release said front edge of the sheet as slitting thereof commences, and means returning said supports with pawls to their original operative position before another sheet is to be cut.

2. A sheet positioning mechanism according to claim 1 comprising two rockable supporting arms for said retractable pawls, first spring means forcing the rocketed arms back into their operative position relative to the front edge and second spring means temporarily holding the arms in such operative position.

3. A sheet positioning mechanism according to claim 2 comprising a stationary and adjustable guide member cooperating with each of said supporting arms to pilot the forward moving sheet.

References Cited by the Examiner UNITED STATES PATENTS 3/1961 Vandeman 271-53 5/1965 Mercer 83419 X 

1. A SHEET POSITIONING MECHANISM FOR USE WITH A SHEET SLITTING DEVICE OF THE TYPE DESCRIBED, COMPRISING A PAIR OF RETRACTABLE STOP MEMBERS FOR THE FRONTAL SHEET EDGE DEFINING ITS POSITION IN FRONT OF THE SLITTING DEVICE, EACH STOP MEMBER CONSISTING OF A SPRING LOADED RETRACTABLE PAWL; SHEET FEEDING MEANS POINT-CONTACTING THE SHEET ALLOWING THE SAME A SKEWING MOVEMENT TO BRING THE FRONT EDGE IN SIMULTANEOUS CONTACT WITH BOTH SAID PAWLS; A RECIPROCABLE 